1. Field of the Invention
The present invention relates to fuel injection systems for internal combustion engines and, more particularly, to fuel delivery pipes for delivering fuel to fuel injectors.
2. Description of the Related Art
An example of a known fuel delivery pipe is shown in FIGS. 33 and 34. As shown in FIG. 33, the fuel delivery pipe has a cylindrical main body 210 and a plurality of injector connecting portions 214 mounted on the main body 210. Further, as shown in FIG. 34, an injector 250 is connected to each of the injector connecting portions 214. Fuel is supplied into the main body 210 of the fuel delivery pipe and then to each injector 250.
The main body 210 is integrally formed of a synthetic resin or a composite of a synthetic resin and other materials. An external wiring connector 218 is integrally formed with the main body 210 and has a connecting terminal 236 to which a fuel injection signal is supplied by external wiring. An injector connector 280 is provided on each injector connecting portion 214 and has a connecting terminal 281. The connecting terminal 281 is connected to a connecting terminal 257 of each injector 250. The connecting terminal 236 of the connector 218 is connected to the connecting terminal 281 of the injector connector 280 by wires 260. The wires 260 are embedded or installed within the main body 210 by injection molding when the main body 210 is molded. Such a fuel delivery pipe in which wires 260 are installed within the main body by injection molding is disclosed, for example, in Japanese Patent Publication No. 3-39194 and Japanese Laid-Open Patent Publication No. 8-303319.
In this known fuel delivery pipe, the wires 260 have a tendency to become distorted as a result of the high molding pressure applied to the wires when the main body 210 is molded. The distortion of the wires 260 may result in wiring defects, such as breakage or short circuits or exposure of the wires 260 on the outer surface of the main body 210.
Japanese Laid-Open Patent Publication No. 10-184490 discloses a connector block for a fuel injector in which the wires are not installed by an injection molding process. The connector block has a plurality of injector connectors and an external wiring connector on the main body. Each of the injector connectors is adapted to be connected to a connecting terminal of the injector. Further, the connecting portion of each connector is adapted to be connected to the external wiring connector. The wires that connect the injector connector and the external wiring connector are embedded in a close relationship within a wire distribution enclosure.
However, in this known connector block, the wires cross or overlap each other within the wire distribution enclosure. Therefore, wiring defects may result, such as breakage or short circuits.
It is, accordingly, an object of the present teachings to provide improved fuel delivery pipes and wiring methods for the delivery pipes, which can reduce or substantially prevent wiring defects, such as breakage or short circuits.
In one aspect of the present teachings, fuel delivery pipes are taught that have a wire distribution enclosure for protecting wires that couple induction signals from an external source to the injectors. Wall-like wiring guides are preferably provided within the wife distribution enclosure. The wires may be wound around or hooked on the wire guides. Preferably, the wire guides may be disposed in a position to change the wiring direction of the wires. The wall-like wiring guides may partition the wire distribution enclosure into sections and the wires may be separately laid in each of the sections. Thus, the wires do not cross each other, thereby reducing or preventing wiring defects, such as breakage or short circuits.
Further, a surrounding wall may be provided to surround the wire distribution enclosure, and connecting terminals of the injectors may extend through the surrounding wall. The surrounding wall may have wire-receiving grooves for passing the wires through the surrounding wall. With such a construction, the wires can be installed within the wire distribution enclosure.
In another aspect of the present teachings, methods are taught for installing the wires without causing the wires to cross each other between an injector independent connecting terminal and injector common connecting terminals of the injectors and an external wiring common connecting terminal and external wiring independent connecting terminals of the external wiring connector. Preferably, such wire installation method include routing a single wire along a wire routing path, connecting the wire to the connecting terminals and removing or cutting out unnecessary or surplus portions of the wire to form a plurality of separate connections. In this case, the wire is routed along a wire routing path, thereby facilitating the wire installation, connection and removal operations. Auxiliary guides are preferably used in the routing step, thereby further facilitating the wire routing operation. The auxiliary guides are preferably not integral with the fuel delivery pipe.